JPH09148985A - Telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excess transmission by extracting a reception level from a reception signal, adjusting master machine side impedance matching in accordance with the level and preventing matching in a high reception level position. SOLUTION: The reception signal in an antenna part 19 is demodulated in a reception part 15 through a variable adjusting part 23 executing impedance matching and a switch 16. An electric field intensity level received in a reception electric field detection part 22 is extracted from the demodulation signal and a control part 20 compares it with a reference electric field intensity level which is previously set. When a slave machine is near, the reception electric field intensity level is higher and a reception state is satisfactory, the control part 20 transmits a control signal so that the impedance matching of the matching part 23 is shifted form a reference value. Thus, a radio signal transmitted form the antenna 19 is reduced and reception sensitivity is reduced. In such a case, the reduction of the reception sensitivity of the antenna 19 can be prevented only by control at the time of transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device including a master unit connected to a telephone line and a slave unit for a call for exchanging data and voice by wireless communication.

[0002]

2. Description of the Related Art Recently, various communication systems have been developed and put into practical use due to the development of mobile communication technology. In addition, digital communication in consideration of information communication is actively performed.

Specifically, a PDC based on the "digital car telephone system standard" shown in RCR STD-27, which is the standard of the Radio System Development Center.
(Personal Digital Cellular Telecommunication Syst
em) and PHS (Person) based on the "2nd generation cordless telephone system standard" shown in RCR STD-28.
al Handy / phone System) is still in existence.

As a result, the terminal can communicate freely anywhere within the service area of the base station that communicates with the terminal that is a mobile station, which is very convenient.

FIG. 4 is a circuit block diagram of a conventional example. This constitutes a PHS system consisting of a master block and a slave block. This master unit block is connected to the speech network 11 for matching with the telephone line, and the AD / DA conversion unit 1 that is connected to the speech network 11 and performs analog-digital conversion and digital-analog conversion.
2, a digital processing unit 13 that performs digital signal processing such as TDMA (Time Division Multiple Access) processing, and a transmission unit that modulates and demodulates a data signal that is exchanged between the slave unit block and transmits the modulated signal to the slave unit. 14, a receiving unit 15 for receiving a modulated voice signal and a modulated data signal coming from a slave unit, a switch unit 16 for switching between transmission and reception, an antenna measurement terminal 17, and for matching the antenna. A matching unit 18, an antenna unit 19, a control unit (CPU) 20 that controls each unit and data,
It is a memory 21 in which a procedure for controlling and controlling data is programmed and each data is stored.

The slave unit block has substantially the same structure as the master unit block, and a description of the same processing block will be omitted. This slave unit block includes a transmitter / receiver unit 51 including a microphone and a speaker, an analog-digital conversion,
AD / DA converter 52 for performing digital-analog conversion
And a digital processing unit 53 that performs digital signal processing such as TDMA (Time Division Multiple Access) processing, and a transmission unit 54 that modulates and demodulates a data signal that is exchanged between the master unit block and the modulated signal to the master unit. A receiver 55 for receiving a modulated voice signal and a modulated data signal coming from the master unit, a switch 56 for switching between transmission and reception, an antenna measurement terminal 57, and an antenna for matching the antenna. A matching unit 58, an antenna unit 59, a control unit (CPU) 60 that controls each unit and data, a memory 61 that stores a program for a procedure for performing control and data control, An operation display unit 62 is provided for performing various operations while being operated by the user. The operation display unit may be provided in the parent device.

In order to make a call using such a device, first, the state of each part is transmitted and the data for setting a call path is exchanged between the base unit and the handset unit. That is, when the operator requests a call by operating the display operation unit 62,
The data signal from the child device is transmitted via the antenna unit 59. When it arrives at the base unit, it is recognized by the base unit through the antenna 19.

As a result, the communication channel between the slave unit and the master unit is set, and the telephone call can be performed. That is,
The transmission voice of the operator is transmitted / received by the transmitter / receiver 51 and the AD / DA converter 5.
2, digital processing unit 53, transmission unit 54, switch 56,
When the signal is transmitted through the matching unit 58 and the antenna unit 59 and arrives at the base unit, the antenna unit 19, the matching unit 18, the switch unit 16, the receiving unit 15, the digital processing unit 13, and the AD / D.
It is sent to the communication partner on the line side via the A conversion unit 12, the speech network 11, and the line.

On the other hand, the data signal from the master unit is transmitted to the slave unit through the opposite route and is notified from the speaker of the transmitter / receiver unit 51.

As described above, the operator can use the slave unit to talk with the other party on the line side via the master unit.

This PHS base unit is generally used at home. Also, in a normal home, an analog telephone is already connected to the telephone line. Furthermore, the number of analog telephones equipped with an analog slave unit such as a cordless phone is increasing. Therefore, in order to connect the PHS master unit and the analog telephone master unit to the telephone line, a separate line must be provided, or
It was realized by distributing by a distributor or branching from a PHS master unit and connecting an analog telephone master unit. However, providing a separate line or a distributor has led to an increase in cost.

Therefore, in order to make the PHS master unit and the analog telephone master unit compatible with each other, distribution from the PHS master unit is the mainstream. FIG. 5 shows a block diagram thereof. First, the telephone line is P
It is connected to each component via the speech network 11 of the HS master device. Here, the speech network 11
The telephone line is pulled out from and is input to the speech network 61 of the analog telephone base unit.

This analog telephone base unit has a speech network 71, an analog processing unit 73 for modulating / demodulating a voice signal for transmission and a voice signal for reception, a transmitting unit 74, a receiving unit 75, a switch unit 76 for switching between transmitting and receiving, an antenna measuring terminal 77, It includes a matching unit 78, an antenna unit 79, a control unit 80, a memory 81 and the like. By performing wireless communication with an analog slave unit (not shown), the operator of the analog slave unit can perform communication as usual.

That is, when there is a call through the telephone line, the PHS master unit and the analog master unit call their respective slave units,
Both handsets can talk and both hands can be used when making a call. However, while one is in use, the other cannot make a call.

Thus, in addition to the currently used analog telephone, the PHS master unit can be easily connected to use the PHS, and the analog telephone is not wasted.

[0016]

Here, as shown in FIG. 6a, the PHS system performs time division multiplexing in a TDMA system with 4 slots for transmission and 8 slots for 4 slots as one cycle. . Send 1-Receive 1 is the main unit-
It corresponds to the down / up between the slaves. Send 2-receive 2,
The same applies to transmission 3-reception 3 and transmission 4-reception 4. That is, four communications are performed in one cycle.
Therefore, it is possible to perform a plurality of communications at the same frequency.

Also, as shown in FIG.
-Reception 1 is 5 [ms] for sending and receiving both the master and slave
(= 200 [Hz]) every time. That is, each antenna outputs at a frequency of 200 [Hz]. Therefore, when the frequency jumps into the baseband band of the analog telephone base unit, a humming sound may be heard and the user may hear the analog handset.

Therefore, within the range of the output of the PHS master unit, the analog telephone master unit is affected by noise at 200 [Hz]. A method of shielding the signal processing unit of the analog telephone base unit is also conceivable, but it is troublesome to install it on the already installed analog telephone base unit. In addition, installing it in a new analog telephone base unit will lead to higher costs.

Therefore, a solution can be considered in the conventional circuit block shown in FIG. This is almost the same as the conventional example of FIG. 4, but a reception electric field detection unit 22 for detecting the reception electric field strength from the slave unit is provided in the master unit block, and the transmission output level is adjusted according to the reception electric field level obtained thereby. To do. Specifically, if the electric field level received from the slave unit is low, the transmission output level is increased to ensure communication with the slave unit, and if the electric field level received from the slave unit is high, the slave unit is The transmission output level is reduced in order to suppress the wasteful power, assuming that the distance between and is short.

However, the transmission output at the antenna measuring terminal 17 is 5 to 12 when the standard is 10 [mW] according to the law.
Since the range is defined as [mW] and a change of about 3 [dB] is allowed, no further change can be made.

Therefore, in this conventional example, since the transmission output is controlled under the restriction of law, when this transmission output is minimized (that is, 10 [mW] is reduced to 5 [mW] = 3 [dB]. ] When it went down), there was a possibility that the analog telephone base unit would be affected.

The present invention prevents that.

[0023]

According to the present invention, there is provided a telephone device comprising a master unit which is connected to a telephone line and wirelessly communicates intermittently, and a slave unit which wirelessly communicates with the master unit. Intensity detection means for detecting the intensity of the radio wave received from the slave unit that wirelessly communicates with the machine, for wireless communication, impedance matching between transmission and reception, and a matching means that can shift the matching by a control signal, According to another aspect of the present invention, there is provided a telephone device including a control unit that generates the control signal according to an output of the reception strength detection unit.

The present invention is also used in a time division system of a digital signal such as TDMA system.

[0025]

FIG. 1 shows a circuit block diagram of an embodiment of the present invention. The same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 23 denotes a variable matching section which is provided in the PHS master unit block and which is controlled by the control section 20 so as not to match matching impedances.

The operation will be specifically described with reference to FIG.

As usual, P received from the antenna section 19 is received.
The reception signal from the HS slave unit is demodulated by the reception unit 15 through the matched (normally matched at 50 [Ω]) variable matching unit 23 and the switch 16. The received electric field detector 22 extracts the electric field strength level being received from the signal obtained by this demodulation and outputs it to the controller 20. The control unit 20 compares a preset reference electric field strength level with the input received electric field strength level. Here, the reference electric field strength level may have a certain width.

When the received electric field strength level is higher than the reference electric field strength level, that is, when the PHS slave unit is near and the reception condition is fairly good, the control unit 20 causes the variable matching unit 23 to match the reference value. A control signal that shifts further is transmitted.

Then, the variable matching section 23 increases or decreases the impedance from 50 [Ω] to bring it into a mismatched state. As a result, the radio signal transmitted from the antenna unit 19 decreases and the sensitivity received by the antenna unit 19 also decreases. However, if you control only when sending,
The sensitivity received by the antenna unit 19 does not decrease.

According to this, the level transmitted from the antenna unit 19 can be reduced by about 10 [dB], so that the influence on the surroundings is significantly reduced. Further, as described above, since the measurement is performed at the antenna measurement terminal 17, even if the output level of the antenna unit 19 is reduced in the present invention, the transmission output regulated by law remains unchanged and there is no effect.

FIG. 2 shows the antenna characteristics, SWR (stan
It shows the relationship between ding wave ratio) and transmission loss.

According to this characteristic, as the SWR (standing wave ratio) increases, the transmission loss also changes in a quadratic curve. Naturally, when the SWR is 1, the transmission loss is 0 [dB].

That is, if the matching impedance is changed from the time of 50 [Ω], the SWR increases and the transmission loss increases.

Next, the radiation gain due to the transmission loss will be described with reference to the antenna radiation gain diagram shown in FIG.

In this figure, the solid line shows a matched 50 [Ω], and the broken line shows a mismatched state. The SWR in this mismatched state is 1
4.

Further, the gain in the horizontal plane (XY) when the antenna is vertically placed is shown in FIG. 10A, and the gain in the vertical plane (YZ) on the same plane as the antenna is shown in FIG.

Therefore, as shown in FIGS. 2 and 3, S
When WR = 14, it is about 6 [dB] compared to when SWR = 1.
Only the gain can be reduced.

Therefore, according to the present invention, as the received electric field strength level becomes larger than the reference electric field strength level, it is possible to gradually reduce the radiation gain.

Further, by using the present invention in combination with other conventional examples, it is possible to suppress an output close to about 10 [dB], which is 6 [dB] added to 3 [dB].

Further, according to the present invention, similar means for detecting the received electric field strength level may be provided on the slave side.

[0042]

According to the present invention, the reception level is extracted from the signal received from the PHS slave unit, the impedance matching on the master unit side is adjusted according to the level, and the impedance matching at the place where the reception level becomes high is not performed. Since they are matched, excessive transmission is prevented. Therefore, it is possible to prevent a 200 [Hz] signal generated by the TDMA method used in the PHS system from jumping into the analog telephone base unit installed near the PHS base unit and adversely affecting it.

In addition to this embodiment, the present invention also performs transmission output according to the received electric field strength level,
The transmission output can be suppressed more. Therefore, PH
Even if the S master unit and the analog telephone master unit are installed adjacent to each other for parallel connection, there is no adverse effect.

Further, by receiving the received electric field strength level,
By providing the configuration for controlling the transmission level in the master unit, the slave unit, or both the master unit / slave unit in this way, it is possible to reduce power consumption and suppress the influence on other wireless devices.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

FIG. 2 is an antenna characteristic diagram of the present invention.

FIG. 3 is an antenna radiation gain diagram of the present invention.

FIG. 4 is a circuit block diagram of a conventional example.

FIG. 5 is a block diagram showing a relationship between a PHS master device and an analog telephone master device.

FIG. 6 is a diagram showing a PHS transmission / reception system.

FIG. 7 is a circuit block diagram of another conventional example.

[Explanation of symbols]

 11 Speech Network 12 AD / DA Converter 13 Digital Processor 14 Transmitter 15 Receiver 16 Switch 17 Antenna Measurement Terminal 19 Antenna 20 Control Unit 21 Memory 22 Received Electric Field Detector 23 Variable Matching Unit

Claims (5)

[Claims] 1. A telephone device comprising a master unit connected to a telephone line and performing wireless communication intermittently, and a slave unit wirelessly communicating with the master unit, wherein the slave unit wirelessly communicates with the master unit. Signal strength detection means for detecting the strength of the radio wave received from the machine, for wireless communication, impedance matching between transmission and reception, matching means that can shift the matching by the control signal, by the output of the reception strength detection means A telephone device comprising a control means for generating the control signal. 2. A telephone device comprising a master unit connected to a telephone line and wirelessly communicating by time division multiplexing of digital signals, and a slave unit wirelessly communicating with the master unit. Receiving strength detection means for detecting the strength of the radio wave received from the slave unit, and matching means capable of performing impedance matching of transmission and reception for wireless communication and shifting the matching by a control signal; A telephone device comprising a control unit for generating the control signal according to the output of the means. 3. TDMA connected to a telephone line
In a telephone device including a master unit that wirelessly communicates by a method and a slave unit that wirelessly communicates with this master unit, a reception intensity that detects the strength of a radio wave received from the slave unit that wirelessly communicates with the master unit. For the wireless communication with the detection means, a matching section that performs impedance matching of transmission and reception and can shift the matching by a control signal, and a control section that generates the control signal by the output of the reception intensity detection means are provided. Characteristic telephone device. 4. A transmission unit, the transmission output level of which is controlled by the control signal, comprising: controlling the transmission output level and the impedance matching / mismatching degree by the output of the reception intensity detecting unit. The telephone device according to any one of claims 1 to 3, which is characterized in that. 5. The telephone device according to any one of claims 1 to 4, wherein the reception strength detection means is provided in at least one of a master unit and a slave unit.